How to unwrap long mesh
I performed a few experiments and I have the following suggestions:


mark a seam on one of the super-long edges.
when unwrapping unselect the two ends.  This will give you the long faces.
after unwrapping the long faces, scale them in the UV/image editor to fill the available space.  If you want to use the entire UV space only scale along the skinny axis ( s x ). 
You will probably need to use a tall texture, or the texture pixels will look stretched in the 3D view.  
If you are not using a tall texture, you should probably scale uniformly and let the texture wrap on the long axis.
you can unwrap the ends separately.
If you do not want to unwrap the ends separately, mark all the edges on the end as seams.
It is possible to have the end polygons overlap the texture coordinates of the long polygons, or just be a different material.  If they are going to be the same material, the texture coordinates should probably have the same scaling applied to them or things might look funny.